FIGS. 4 and 5 show a conventional cushion device which is connected to the bottom bracket 10 of a bicycle and has two lugs 11 extending radially outward from the bottom bracket 10, a connecting member 12 pivotally connected between the two lugs 11 with a pin 16 extending through the connecting member 12. The two chain stays 13 extend from the connecting member 12 with the rear wheel (not shown) located between the two chain stays 13. Therefore, when the bicycle is ridden on a serrated road, the rear wheel connected between the two chain stays 13 jumps up and down to absorb the shocks. Two pairs of bearings 15 are respectively connected to two ends of the pin 16 and received in the two lugs 11, a bolt 14 extending into one of two ends of the pin 16 so as to position the two bearings 15. The cushion device will let the pin 16 bear most of the force when the rear wheel jumps up and downward so that the pin 16 has to be manufactured by tough material which is expensive. In addition, when the force is transferred to the pin 16, the two bearings 15 have the tendency to unexpectedly shift toward each other so that the bearings 15 could loose their function. Furthermore, dust is easily entered into the gaps between the bearings 15, the pin 16 and the bolt 14, especially when the bicycles equipped with the cushion device are ridden on rugged roads.
The present invention intends to provide a cushion device wherein the force transferred to the cushion device is dispensed by two cone-shaped members which are engaged with the connecting member and the pin extends through the two cone-shaped members and the connecting member so that the above-mentioned problems are well mitigated.